Linux in a Nutshell, 6th Edition

Name

vmstat

Synopsis

vmstat [options] [interval [count]]

System administration command. Print report on virtual memory statistics, including information on processes, memory, paging block I/O, traps, system and CPU usage. vmstat initially reports average values since the last system reboot. If given a sampling period interval in seconds, it prints additional statistics for each interval. If specified, vmstat exits when it has completed count reports. Otherwise, it continues until it receives a Ctrl-C, printing a new header line each time it fills the screen.

Options

-a

Display active and inactive memory.

-d

Display disk statistics.

-f

Display the number of forks since the system was booted.

-m

Display the names and sizes of various kernel objects stored in a cache known as the slab layer. Also see the slabtop command.

-n

Don’t print new header lines when the screen is full.

-p partition

Display detailed statistics for the specified partition.

-s

Display various event counters and memory statistics.

-S units

Switch the output units. Possible values are k, K, m, or M.

-t

Add a timestamp to output.

-V

Print version number, then exit.

VM mode fields

procs

r

Processes waiting for runtime.

b

Uninterruptible sleeping processes.

memory

swpd

Virtual memory used, in kilobytes.

free

Idle memory, in kilobytes.

buff

Memory used as buffers, in kilobytes.

cache

Cache memory, in kilobytes.

inactive

Inactive memory, in kilobytes, displayed with -a.

active

Active memory, in kilobytes; displayed with -a.

swap

si

Memory swapped in from disk each ...